jamit
Hazard to Others
Posts: 375
Registered: 18-6-2010
Location: Midwest USA
Member Is Offline
Mood: No Mood
|
|
solvent distillation
if there is a post on this subject I would appreciate it if someone would direct me to it.
I wanted to know if there's anyone out there who have purified their otc solvents via distillation. Solvents like toluene, denatured alcohol,
acetone, xylene, and methyl ethyl ketone.
From my reading on this board and other forums, many solvents that you buy at home depot or hardware stores have unknown impurities added. I want to
remove these impurities and so before doing it I wanted to know if there are any tips or suggestions you might have for me.
I would like to hear from those who have actually done the experiment in purifying solvents. thanks in advance.
|
|
|
Contrabasso
Hazard to Others
Posts: 277
Registered: 2-4-2008
Member Is Offline
Mood: No Mood
|
|
Each distillation needs to be considered separately! Alcohol is denatured to discourage people drinking it tax free. SO the denaturing ingredients are
specified to be difficult to separate out.
|
|
|
Melgar
Anti-Spam Agent
Posts: 2004
Registered: 23-2-2010
Location: Connecticut
Member Is Offline
Mood: Estrified
|
|
I've never distilled those solvents. Sure, they can pick up water, although that's doubtful in a metal can, but that's not much of a problem unless
you need really dry conditions. And in that case, I dry the solvent over CaCl2. I tend to feel that my bumbling self is more likely to add
contaminants than remove them during the process of distillation. :p
|
|
|
Al Dehyde
Harmless
Posts: 3
Registered: 26-2-2011
Location: Outback Aus
Member Is Offline
Mood: Steam Distilled
|
|
Re: solvent purification
Hi Guys, thought this topic would be perfect for my first post, im no expert, i have little experience in organic chemistry and am here to learn and
share information, but what type of question is this? there is so much readily available information out there, do a simple google search if you dont
have access to textbooks etc i will say- start with research on autoignition temperatures and flash points before you do anything, types of
distillations and setups, boiling points, dont consider distillation untill you know the properties and hazards of the compound and the correct
distilling method and setup required.
For your reference i have safely distilled/purified/separated otc solvents and obtained anhydrous pure products.
|
|
|
BromicAcid
International Hazard
Posts: 3227
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
Several years ago I decided I would try to distill my 'xylenes' before use. About 80% of the material came over within range, the remainder in the
pot darkened to a red / orange oil throughout the course of the distillation that refused to come over even up to 170°C in the pot. What it was I
don't know.
|
|
|
antibody
Harmless
Posts: 38
Registered: 4-2-2011
Member Is Offline
Mood: No Mood
|
|
read up on fractional distillation
http://en.wikipedia.org/wiki/Fractional_distillation
or if the BPs of your solvents have more than 25°C difference, then use simple disitillation, ie no column required
|
|
|
Nilson
Harmless
Posts: 10
Registered: 21-2-2011
Location: Virginia
Member Is Offline
Mood: No Mood
|
|
that 25 C difference is not a set in stone difference to go by. It depends on the skill of the chemist, additionally how many times you want to
re-distill, and the properties of the chemicals you're trying to separate (azeotropes).
But, I will say it is not a bad thumb-rule to go by 
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
I rarely distill any of my OTC solvents unless they contain something I dont want. Right now my favorite is a very large jug that only contains MeOH,
DCM and Toluene. It has proven the cheepest MeBn I have found yet so I distill that. Other then that not much else feels worth it. Im starting to
question my actions however after seeing Bromicacids post because normally impuritys are not worth my time to be concerned with the form of chemistry
I do however 20% is a large number that I would really like to know more about. I think it should be a rule of thumb to atlest distill once to get an
idea of what your dealing with then go from there. Im a better preacher then a follower though. .
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
|
|
|
Intergalactic_Captain
Hazard to Others
Posts: 227
Registered: 4-9-2004
Location: somewhere where i don\'t know where i am
Member Is Offline
Mood: frabjous
|
|
The most important thing to consider with OTC solvents is what their primary use is - After that, what manufacturer actually makes them (often the
label on the can will show the distributor instead).
Cleaning solvents, like paint-strippers and goo-gone, tend to be combined with various "goos" to decrease their volatility and increase their
usability time. As such, these will practically always need to be distilled to be useful.
Pipe-fittings solvents, like those used for PVC, ABS, and CPVC, tend to be mixtures of several solvents and dyes, sometimes plastic fillers. These
formulations vary wildly between manufacturers - and end uses. Cleaners and primers for small-diameter pipes tend to contain large amounts of MEK,
acetone, and THF, along with dyes and free of filler. The cements for the same pipe usually contain a relatively small amount of filler. For larger
diameter pipes, the acetone and THF content tends to lower favoring MEK and larger amounts fillers - You need a longer working time with bigger pipes,
hence the lower volatility of your glue/solvent.
Solvents for paints and stains generally tend to be the purest, especially in the professional sector - If you have a Sherwin-Williams store nearby,
check their online inventory - You might be surprised by what they carry. Don't be afraid to call up each store - They commonly stock some unusual
solvents on the odd chance that someone has a specialty project - I was able to get a gallon of toluene for ~$20USD last year in this way. That
aside, these solvents tend to be "cleaner" as their end-use depends on it. They may still be solvent mixtures (xylenes, napththa, "mineral spirits,"
"lacquer thinner"...), but they don't generally have any high-boiling or polymeric constituents. As extration solvents, they are generally useful
as-is.
...On a side note, I not long ago found petroleum (gas, petrol, wherever you are) to be a useful source of "petroleum ether" type solvents. After a
few experiments, I was able to repeatably separate 3 distinct fractions - 40-60degC, 60-90degC, and 90-120degC - About 1/3 was the lowest, the other 2
making up about 1/2, and the remainder in the pot being very high-boiling stuff that I never characterized. I was primarily interested in toluene,
but as per US regulations, you're likely to never find it. The low-boiling fraction, however, proved to be incredibly useful as a petroleum ether
substitute for extractions.
If you see me running, try to keep up.
|
|
|
Arthur Dent
National Hazard
Posts: 553
Registered: 22-10-2010
Member Is Offline
Mood: entropic
|
|
Quote: Originally posted by Intergalactic_Captain  | | The most important thing to consider with OTC solvents is what their primary use is - After that, what manufacturer actually makes them (often the
label on the can will show the distributor instead). |
Thanks for the suggestions, I have been on a quest to gather the most useful solvents in home chemistry at the lowest cost, either by finding
inexpensive and unexpected sources, by distilling mixtures of solvents, or by synthetizing them on my own. Of course, those are the most stable
solvents, because when I need the really volatile stuff, or stuff that have a very short shelf life, I either make it in-situ or try to find an
acceptable substitute.
Are you talking about gasoline? I've thought often of the goodies that are in the stuff at the pump, but never had the gonads to try to distill the
stuff, the thought of a flask filled with gasoline, boiling away on a hotplate, even if all my ground glass is perfectly sealed, scares the crap out
of me! 
Robert
[Edited on 3-3-2011 by Arthur Dent]
--- Art is making something out of nothing and selling it. - Frank Zappa ---
|
|
|
aonomus
Hazard to Others
Posts: 361
Registered: 18-10-2009
Location: Toronto, Canada
Member Is Offline
Mood: Refluxing
|
|
I recently learned that some (not all!) LC grade solvents are produced by taking lower grades of solvent in a reactor with concentrated sulfuric acid
(the two must be immiscible), bringing the mixture to reflux with lots of agitation until all the organics are digested out of the solvent and all the
water has been pulled out. Then a phase separation followed by distillation in glass cleans up the solvent. That is actually quite scary on the small
scale.
Also of note is the fact that the sulfuric acid comes out black or otherwise significantly colored (which might explain some grades of sulfuric acid).
|
|
|
jwarr
Hazard to Self
Posts: 85
Registered: 25-6-2009
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Sedit | | I rarely distill any of my OTC solvents unless they contain something I dont want. Right now my favorite is a very large jug that only contains MeOH,
DCM and Toluene. It has proven the cheepest MeBn |
By MeBn did you mean xylene or did you mean toluene (MePh)?
[Edited on 31-3-2011 by jwarr]
|
|
|
mr.crow
National Hazard
Posts: 884
Registered: 9-9-2009
Location: Canada
Member Is Offline
Mood: 0xFF
|
|
If you think you can distill Toluene out of "lacquer thinner" then its not worth it. I tried washing out the methanol and methyl ethyl ketone with
water but distilling only yielded 1/4 the volume of pure toluene.
Double, double toil and trouble; Fire burn, and caldron bubble
|
|
|
hkparker
National Hazard
Posts: 601
Registered: 15-10-2010
Location: California, United States
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by BromicAcid | | Several years ago I decided I would try to distill my 'xylenes' before use. About 80% of the material came over within range, the remainder in the
pot darkened to a red / orange oil throughout the course of the distillation that refused to come over even up to 170°C in the pot. What it was I
don't know. |
I saw something like this in a ReactionFactory video where they produced benzene from sodium benzoate and sodium hydroxide.
http://www.youtube.com/watch?v=S8rtyRnZZMU
My YouTube Channel
"Nothing is too wonderful to be true if it be consistent with the laws of nature." -Michael Faraday
|
|
|
overload
Hazard to Self
Posts: 66
Registered: 9-7-2011
Location: USA
Member Is Offline
Mood: miserable fat slave
|
|
The first solvent is DCM bought from ebay and the second is hardware store toluene. Neither of these solvents are acceptable. Fractional distillation
is an absolute must before using these solvents in any type of laboratory experiment were maximum purity and yield are desired.
 
Even after distilling the DCM bought from ebay I am still left with residue. The residue is less than before and leads me to believe that I may have
contaminated it with minerals from the water I used to clean my glassware but there is no way to be certain since I did use distilled water to rinse
out any tap water residue. The other possibility is the impurities are being carried over with the dichloromethane. What puzzles me is when I had
finished the distillation the DCM was completely clear but once I filled the glass bottle I found a cloudy layer was forming at the bottom. After
swirling it around I noticed it looks like actual particles.
[Edited on 14-10-2011 by overload]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
